1. Field of the Invention
The present invention relates to a method for manufacturing a liquid crystal display (LCD), and especially to a method for curing a sealant of an LCD panel.
2. General Background
A liquid crystal display panel generally comprises two glass substrates, a peripheral sealant, and liquid crystal. The sealant is printed on one of the glass substrates, and is then adhered to the other glass substrate. The substrates and the sealant cooperatively form a space therebetween, and then the liquid crystal is filled into the space.
There are generally two methods used for filling the liquid crystal into the space. The first method is to fill the liquid crystal through filling ports. This method comprises the following steps: firstly, printing a sealant on a first glass substrate, wherein the sealant is rectangular and has one or more gaps that function as filling ports; secondly, combining a second glass substrate with the first glass substrate and curing the sealant, wherein a space is enclosed by the sealant and the two glass substrates; thirdly, immersing the filling ports in liquid crystal in a vacuum chamber; and finally, introducing gas into the vacuum chamber to make the liquid crystal fill up the space.
The second method is the so-called one-drop-fill (ODF) method. This method comprises the following steps: firstly, printing a sealant on a first glass substrate, wherein the sealant is rectangular and continuous, and a space is enclosed by the sealant and the first glass substrate; secondly, putting liquid crystal into the space drop by drop using a dispenser; and finally, combining a second glass substrate with the first glass substrate and curing the sealant. The ODF method can save much time and liquid crystal material, especially in a large size liquid crystal display panel manufacturing process.
Referring to FIG. 8, a conventional liquid crystal display panel 1 includes a first glass substrate 10, a second glass substrate 20 opposite from the first glass substrate 10, liquid crystal 50 sealed between the first substrate 10 and the second substrate 20, and a sealant 70 for sealing the first substrate 10 and the second substrate 20. A photo resist 40 and a black matrix 30 are arranged on an inner surface of the first substrate 10.
Referring to FIG. 9 and FIG. 10, a method for adhering the two substrates 10, 20 comprises the follow steps: firstly, providing the first substrate 10 and the second substrate 20 on a worktable 80, forming a photo resist 40 and a black matrix 30 on the first substrate 10, and then printing a sealant 70 on the first substrate 10, wherein the sealant 70 is rectangular and continuous; secondly, putting liquid crystal 50 on the second substrate 20 drop by drop using a dispenser; thirdly, aligning and combining the first substrate 10 and the second substrate 20 in a vacuum chamber; finally, curing the sealant 70 by applying ultraviolet (UV) light, whereby the first substrate 10 and the second substrate 20 are securely attached to each other. A liquid crystal display panel 1 is thus obtained.
However, during the process of curing the sealant 70 by applying the UV light, a part (indicated with A) of the sealant 70 is blocked by the black matrix 30, whereby the sealant 70 cannot be completely cured by the UV light. In addition, because the liquid crystal 50 directly contacts the sealant 70, some of the uncured sealant 70 may get mixed with the neighboring liquid crystal 50. Therefore, a uniform performance of the liquid crystal display panel 1 may be impaired. Furthermore, even though the part A of the sealant 70 is not blocked by the black matrix 30, a light intensity of the UV light incident on a side of the first substrate 10 is generally unduly low and not enough to cause the sealant 70 to be completely cured.
What is needed, therefore, is a method for curing sealant that can improve the performance of a liquid crystal display panel as regards a uniformity of display quality. What is also needed is an LCD panel manufacturing method that can yield a liquid crystal display panel having improved uniformity of display quality.